Apparatus for pulverizing and separating granular materials



April 29 1924.

W. J. BELL APPARATUS FOR PULVERIZING AND SEPARATING GRANULAR MATERIALS 2Sheets-Sheet 1 Filed June 16 1920 Ill llllillllll attozwugs 1,491,841 w.J. BELL APPARATUS FOR PULVERIZING AND SEPARATTNGGRANULAR MAT ERIAL SApril 29 1924.

Filed June 16 1920 2 Sheets-Sheet z Patented Apr. 29, 1924.

UNITED STATES A 1,491,841 PATENT. OFFICE.

WILLARD J. BELL, OF NEWAYGO, MICHIGAN.

APPARATUS FOR PULVERIZING AN D SEPARATING GRANULAR MATERIALS.

Application filed June 16, 1920. Serial No. 389,309.

To all whom it may concern:- Be it known that I, WILLARD J. BELL, acitizen of the United States, and a resident of Newaygo, county ofNewaygo, and State.

arating granular materials, is directed pri marily to an improved typeof pulverizing drum provided with means particularly adapted for soagitating the material passing therethrough that an air blast forcedthrough the interior of the drum is enabled to pick up all of the veryfine particles and dust and continuously remove them from the presenceof the other larger particles of material. To the accomplishment of theforegoing and related ends, said invention, then, consists of the meanshereinafter fully described and particularly pointed out in the claims.

The annexed drawing and the following description set forth in detailcertain mechanism embodying the invention, such disclosed meansconstituting, however, but one of various mechanical forms in which theprinciple of the invention may be used. a

In said annexed draw-ing: v

Fig. 1 is a side elevation of my improved apparatus; Fig. 2 isalongitudinal central section through a pulverizing drum; and Fig. 3 is asection on the line 33, Fig. 2.

The general arrangement of the apparatus shown in the drawings issimilar to that described in my co-pending application, Ser1al No.367,753, filed March 22, 1920. The apparatus consists of a pulverizingdrum 1 rotated by means of an external gear and discharging through atrunnion bearmg 3 into a discharge conduit 4, which leads to a feedmechanism 5 for distributing the material over the surface of one ormore screening machines 6. In the screening machines the over-size andunder-size material issue from chutes 7 and 8, respectively, and arethen removed into separate bins, or, if desired, the over-size materialmay be again passed through the pulverizing drum for still finercrushing.

The material is fed into the drum through a trunnion bearing 10 and froma hopper 11, which opens into a conduit 12 leading through the trunnionbearing and into the cylinder. In the conduit 12 there may be' mounted aspiral conveyor of the usual type,

the location of which is indicated at in- Fig. 1 for feeding thematerial into the drum, the shaft 13 of this spiral conveyor beinghollow and extending rearwardly through the conduit 12 where it isconnected to an air conduit 14 for supplying an air blast to thecylinder. The shaft 13, for driving the s iral conveyor, is formedhollow, the air b ast shaft.

Air under pressure is suppliedby means of a pump 15, through a conduit14, and is then passed through the interior of the pul- 'verizing drum.After discharging from the other end of the pulverizer it goes through aconduit 17 into a centrifugal collector 18, from which the air isreturned through a conduit 19 to the pump 15, while the granularmaterial and dust which is separated from the air in the collector isdischarged through a chute 20 and may then be admitted either to theseparator or lead directly to storage bins as may be desired.

In Fig. 2 I have shown the interior construction of the drum 1. Thisdrum is provided with a-series of spaced chambers 21, 22 and 23, whichare connected by conduits 24 and 25, which are of reduced cross-sectionpassing through this hollow compared to the maximum cross-section of Ithe three chambers and are provided with a series of shelves orinternally extending flanges in the form of angles 26. By thisconstruction it is possible to progressively grind the material with theuse of a considerably less number of grinding elements, which areusually in the form of balls or pel bles 27, thanis possible in theordinary pulveri'zing' drum. The coarsest particles are crushed in thechamber 21 and when brought to approximately the size of the ballstherein they are discharged through the conduit 24 into the chamber 22,where they are crushed still further and are then discharged through theconduit 25'into the chamber 23. In this" last chamber they are crushedto approximately the fineness desired and are then discharged andscreened in the apparatus already described. 7

' Apulverizing drum is notoriously ordinarilyv ineflicient in action andwasteful of power because the finely crushed material packs around thelarger uncrushed lumps and around the pebbles andcushions the grindingaction of the pebbles or balls.

end of the .apparatus, and all of the time that this finely crushedmaterial is present it is retarding the further crushing action, and isalso requiring power to lift it up the sides of the drum as the latteris rotated.

The crushing action in the present pulverizing drum is similar to thatsecured in the drum of my United States Patent No. 971,108, in that thematerial is rapidly discharged from one chamber to another, and eachchamber is so formed as to vsecure a maximum crushing action with aminimum of dead material, and with a minimum of power. By placing thethree chambers in the manner shown and interposing restricted conduitsbetween them equipped with devices for lifting material and causing itto fall transversely of the conduit it is possible, by forcing an airblast through the entire apparatus, to immediately remove all of thevery fine particles from the presence of the coarser ones. As thematerial is carried into the conduits 24 and 25 it is lifted by theshelves or angles upon rotation of these conduits, and is then droppedback to the bottom of the conduits and passed transversely across theair blast which is forced through the entire drum. The air blast is ofsufficient strength to carry with it all of the relatively finematerial, which is then separated out from the air in the collector 18and returned either to the screening machines or the bins.

It is immaterial whether the pulverizing drum is covered by means of anenclosing shell 30, as shown in Fig. 1, or is merely built u of thevarious chambers and conduits rigidly fastened together as shown in Fig.2, as the action in eithercase is of course the same. The presentapparatus requires much less power for its operation than a pulverizingdrum of the usual type and of equal capacity, and present types of drumscan be changed into the present apparatus by inserting in the drums theconical chambers and connecting conduits, which I have shown in Fig. 2,and also of course by equipping the pulverizing drum with means forsupplying a continuous air blast through the entire drum.

Other modes of applying the principle of my invention may be employedinstead of the one explained, change being made as regards the mechanismherein disclosed, provided the means stated by any of the followingclaims or the equivalent of such stated means be employed. I

I therefore particularly point out and distinctly claim as myinvention 1. In an apparatus of the dry air blast, pulverizing type, apulverizing drum having a plurality of chambers in axial alinement andspaced relation, a conduit of restricted area rigidly connecting andspacing each two adjacent chambers, means for rotating said drum, saidchamber having conical end walls for diverting pulverized material intosaid conduits, means provided on the interior of said conduit fordropping said material across the space within said conduit and meansadapted to force an air blast through said chambers and said conduit forcarrying said pulverized material progressively through saidinterconnected chambers and conduits.

2. In an apparatus of the dry air blast, pulverizing type, a cylindricaldrum provided with end plates, hollow trunnions provided on said endplates, driving connections provided on the outside of said drum forrotating the same, a plurality of hollow members of frusto-conicalcross-section fitted transversely within said drum, the bases ofadjacent members being placed in close contact to form pulverizingchambers, collars formed on the smaller ends of certain of said membersto form conduits with the collars of adjacent members, a plurality oflongitudinally extending flanges provided on the inner surface of theconduits located between adjacent pulverizing chambers for dropping thematerial operated on across the space within said conduits, and air andmaterial inlet and outlet passageways provided by the hollow trunnionsconnected with said end plates.

Signed by me, this 9th day of June, 1920.

. LARD J. BELL.

